Sizing



Patented Oct. 21, 1942 SIZING Daniel I. Strain, Del all! to lLduPontdeNemourslCompa-y,Wihnington.Del.,acorporationofDeiawa-m No Drawing. A

September 21, 1940,

pplieation Serial No. 357,755

17 Claims. (Cl. 117-47) This invention relates to an improved sizing composition which is suitable for use on knitting yarns composed of synthetic linear polyamides. More particularly, this invention relates to an improvement of the sizing compositions described and claimed in the copending application of Edgar W. Spanagel, Serial No. 357,757, filed of even date herewith.

The above-said Spanagel application makes detailed reference to the critical requirements of a size suitable for use on the smooth, round filament yarns composed of synthetic linear polyamides in the knitting of ladies sheer hosiery. The term "synthetic linear polyamide" as used throughout the specification and claims is intended to refer specifically to the material disclosed in U. 5. Patents Nos. 2,071,250, 2,130,523 and 2,130,948.

In accordance with said Spanagel application, excellent sizing compositions for synthetic linear polyamide yarns to be used in knitting sheer, fullfashioned hosiery can be prepared from polyvinyl alcohol, or a water-sensitive derivative of polyvinyl alcohol and boric acid. These new compositions, characterized by a low viscosity and consequent high degree of solubility and ease of application, adhere well to the smooth, round polyamide filaments, bind the filaments together well, impart to the yarn good running properties on full-fashioned knitting machines, protect the full-fashioned stocking fabric well from snags and runs, prevent serious edge rolling of the fullfashioned stocking fabric, and are readily removed by hot water.

It was further found that these polyvinyl alcohol-boric acid sizes, or polyvinyl alcohol derivative-boric acid sizes, will adhere to the yarn better if an anchor coat (or a sub-coat) of tannic acid is applied to the yarn before applying the size. The tannic acid apparently adheres very well to the synthetic linear polyamide and also to the size. However, it has been found that the adherence of the size to the yarn is improved by the tannic acid only if the tannic acid coat is applied first and that a single mixture of the two applied in one step does not produce a wellsized yarn having good full-fashioned hosiery knitting properties, nor does the application of a coat of tannic acid on top of a coat of the size produce a sized yarn having good full-fashioned hosiery knitting properties. The proper ratio of tannic acid in the anchor coat to the size coat im parts astonishingly good snag resistance and running properties to yarn sized in accordance with Moreover, it has'been found that the tannic acid anchor coat decreases the water-sensitivity of the size coat suflicientLv to make possible conditioning of the sized polyamide yarn over water. This is very advantageous because of the practical ease of controlling such a conditioning process. The use of tannic acid under-coatings in the sizing oi. yarn is described and claimed in the copending application of E. W. Spanagel and R. W. Maxwell, Serial No. 357,756 filed of even date herewith.

It is an object of the present invention to improve the above-said polyvinyl alcohol-boric acid sizes, or polyvinyl alcohol derivative-boric acid sizes, by the addition thereto of small amounts of polyethylene oxide (polyethylene glycol).

Other objects of the invention will appear hereinafter.

It has been found that a small amount of polyethylene oxide serves as a plasticizing agent for the polyvinyl alcohol-boric acid and polyvinyl alcohol derivative-boric acid. The polyethylene oxide is a polymerization product obtained from ethylene oxide. Polyethylene oxides having a molecular weight from 282 to 10,000 are very suitable for use in accordance with the present invention. For best' results it is preferred, however, to use polyethylene oxide having a molecular weight of 1,000 to 5,000.

Previously known plasticizers for these polyvinyl alcohol-boric acid sizes, or polyvinyl alcohol derivative-borlc acid size compositions greatly increase the accumulation of size on the knitting machine parts during knitting, thus causing numerous press-offs and deformed stitches. On the other hand, polyethylene oxide not only does not greatly increase the accumulation of size on the knitting machine parts but actually decreases the accumulation of the size on the needles. This is a most surprising and valuable result for it permits the knitting during periods of very high relative humidity (80-100%) or when the cones are conditioned over water. The use of the polyethylene oxide plasticized size with or without an anchor coat of tannic acid is particularly advantageous for yarn that is to be twisted after the sizing operation.

The following examples are given to illustrate preferred sizing compositions and preferred methods of applying the same. The details set forth in the examples are not, however, to be considered as limitative of the invention. The percentages set forth in the examples designate the preferred method as hereinafter described. the percentages by weight.

Example I A size solution is prepared comprising 8% of partially saponified polyvinyl acetate having a saponification number of 140 and a viscosity of 4 centipoises in a 4% aqueous solution at 20 C., 1.6% boric acid, 1.2% polyethylene oxide having a molecular weight of approximately 1,500 and 89.2% water. The size is applied on-the-run in a machine built much like a coning machine, to a 30-denier, 10-filament, 30-turn polyhexamethylene adipamide yarn by passing the yarn over rotating size roll dipping into the size solution. The room temperature is 88 F. and the relative humidity 50%. About 3.5% of the size, based on the weight of the yarn, is applied. After drying the yarn is resized, applying an additional 3.5% of size. The sized yarn is coned while applying approximately of a vegetable oil. The yarn knits well on a full-fashioned knitting machine even when conditioned over water (85-100% relative humidity). The size is readily removed by washing in hot water or in hot, soapy water.

Example If The method outlined in Example I is carried out with a 30-denier, '-ii1ament, 30-tum polydecamethylene sebacamide yarn. The yarn has excellent knitting and snag resisting properties when knit into a sheer, full-fashioned stocking.

Example III A 30-denier, 10-fllament, 30-turn polyhexamethylene sebacamide yarn is sized, dried and coned in accordance with the method outlined in Example I. The sized yam has excellent knitting and snag resisting characteristics.

Example IV A 30-denier, 10-ii1ament, 2-turn yarn prepared from polyhexamethylene adipamide is put on an uptwister and given 28 turns additional twist while applying a 0.25% coat of tannic acid to the yarn just subsequent to the twisting operation and just prior to the winding up of the 30- tum yarn by passing the 30-tum yam through a dip trough containing an aqueous solution comprising 1% tannic acid and 0.15% oxalic acid. After drying, the yarn is sized with a solution comprising 7.5% partially saponifled polyvinyl acetate having a saponification number of approximately 140 and a viscosity of approximately 5 centipoises in a 4% aqueous solution at 20 C., 1 polyethylene oxide having a molecular weight of approximately 1,500, and approximately 91.5% water. The yarn is coned while applying 3.5% of olive oil. The resulting yarn is found to knit well on a standard full-fashioned knitting machine. The size is removed by washing the fabric in a hot water solution containing 0.1% hydrated trisodium phosphate, 0.1% oxalic acid and 0.5% fatty alcohol sodium sulfate.

Example V A yarn, such as is described in Example IV having only 2 turns of twist is coated with tannic acid by passing the yarn over a size roll dipping into a 5% solution of tannic acid in such a. manner as to apply a 0.2% coat of tannic acid to the yarn. The yarn is then sized with a sizing composition, such as is described in Example I, and is then coned while applying teaseed oil. The yarn is later twisted to 30 turns per inch twist, set and coned. The yam knits well and the size is readily removed by hot water or hot, soapy water.

Example VI A 30-denier, 10-filament yarn prepared from polyhexamethylene adipamide is given 2 turns per inch of twist on a downtwister while applying a 0.2% coat of tannic acid to the yarn. The yarn is then sized with a sizing composition, such as is described in Example IV, and is then coned while applying an alkaline emulsion of a vegetable oil. The yarn is later twisted to 30 turns per inch twist, set and coned. The yarn knits well and the size is readily removed by hot water or hot, soapy water.

The present invention broadly contemplates the preparation of sizes from polyvinyl alcohol and water-sensitive derivatives of polyvinyl alcohol, together with boric acid and polyethylene oxide. Such sizes are generally suitable for sizing of synthetic linear polyamide yam which is to be used in the knitting of sheer, full-fashioned hosiery. Thus, water-sensitive polyvinyl compounds in which 1% to 50%, and preferably 20% to 50%, of the carbon atoms of the polyvinyl chain are attached to hydroxyl groups (such compounds being hereinafter referred to as hy-' droxylated polyvinyl resin) when' treated with boric acid and containing a polyethylene oxide produce very desirable yarn sizes. The polyethylene oxide is preferably present in an amount between 5% and 30% based on the weight of the hydroxylated polyvinyl resin.

The water-sensitive derivatives of polyvinyl alcohol which have given particularly good results in combination with polyethylene oxide are the partial esters of polyvinyl alcohol such as the partial acetates, the partial propionates, the glycolic acid esters, the partial formates, and the partial lactates; the partial ethers of polyvinyl alcohol such as the glycol ethers, the glycolic acid ethers, the methyl ethers, and the ethyl ethers; the partial acetals of polyvinyl alcohol such as the partial formal, the partial acetal, the partial glyoxal, the partial propional, and the partial butyral; the partial ketals of polyvinyl alcohol such as ethylmethyl ketal.

Likewise, water-sensitive derivatives of polyvinyl alcohol produced by interpolymerization of polyvinyl esters with small proportions of other components such as vinyl chloride, methyl methacrylate, methacrylic acid (produced by saponification), maleic anhydride, methyl vinyl ketone and unsymmetrical dichloroethylene will be suitable for use, in combination with polyethylene oxide, for the production of boric acid sizes in accordance with this invention.

The partial acetate esters, and the partial formals, of polyvinyl alcohol, when used in accordance with the practice of this invention, have given outstanding results in sizing synthetic linear polyamide full-fashioned hosiery knitting yarns.

Although partially saponified or hydrolyzed polyvinyl acetates having saponification numbers from to and viscosities from 4 to 6 centipoises in 4% solutions at 20 C. modified with 20% to 22.5% boric acid and 5% to 30% polyethylene oxide (percentage based on the weight of the polyvinyl acetate) are particularly useful for sizing synthetic linear polyamide full-fashioned hosiery knitting yams, numerous other partially saponified polyvinyl acetates and various mixtures and combinations thereof lie within the scope of the present invention.

Partially saponified polyvinyl acetate having saponification numbers of between 10 and 300,

or even somewhat lower than or higher than 300, may be used to advantage in sizing synthetic linear polyamide yarns which are to be used in the knitting of sheer, full-fashioned hosiery. For better and more consistent results, however, it is much to be preferred to use a partially saponifled polyvinyl acetate having a saponiiication number between 40 and 220.

The saponiiication number of the partially saponifled polyvinyl acetate. as used herein, is defined as the number of milligrams of potassium hydroxide required to completely saponify one gram of the partially saponifled polyvinyl acetate sample.

The term partially saponifled polyvinyl acetate is intended to include polyvinyl acetate which has been partially, hydrolyzed by other means than saponification with alkali.

Partially saponifled polyvinyl acetates having viscosities from 1.5 to 20 centipoises in a 4% solution at 20 C. are useful in accordance with this invention. The viscosity should be deter mined on a 4% aqueous solution at 20 C., using 1 a Hoeppler viscosimeter (manufactured by Gebrueder Haake, Medingen, Germany).

The water-sensitive hydroxylated polyvinyl resins are preferably-used in solutions containing from 3% to 12% of the resin.

As above indicated, the partial formals of polyvinyl alcohol are also particularly useful. Formals of polyvinyl alcohol containing 10% to 30% of formal and having 5% to 20% of boric acid, based on the weight of the formal, are preferred.

Although particularly desirable results are obtained with sizes comprising a water-sensitive hydroxylated polyvinyl resin, boric acid and polyethylene oxide, when the boric acid used constitutes approximately 20% to 22.5% of the weight of the said polyvinyl resin, it should be understood that boric acid may be used with the water-sensitive hydroxylated polyvinyl resin in the preparation of sizes containing other proportions of boric acid. The amount of boric acid required to give good running properties has been found to vary with the particular hydroxylated polyvinyl resin used. To obtain the best re sults, the amount of boric acid to be used will vary between 5% and based on the weight of the said resin. One skilled in the art can formulate sizes with increasing amounts of boric acid and readily determine the optimum concentration.

Using a polyvinyl acetate having a saponification number of 140 and no other agent for reducing its water-sensitivity, at least 18% boric acid is generally required to give fair running properties. With a polyvinyl acetate having a saponiflcation number of 234 only 12.5% boric acid gives desirable results, but this is practically all the boric acid that this partially saponifled polyvinyl acetate will tolerate without precipitating from solution. Likewise, with polyvinyl acetate having a. saponification number of 140 and 10% aluminum acetate as an auxiliary agent, it is possible to reduce the boric acid concentration to 10% and still retain fair running properties. 0n the other hand, the use of less than 5% boric acid has never given sizes with attractive running properties, except when the size was undercoated with tannic acid. Partially saponifled polyvinyl acetates will tolerate proportions of boric acid up to approximately 24% and possibly higher in some cases. It is, therefore, to be understood that in practicing this invention, proportions of boric acid up to the limit of the tolerance of the polyvinyl material may be used in preparing the sizing composition. The limit of tolerance of the polyvinyl material for the boric acid is that percentage of boric acid based on the weight of the polyvinyl material which can be barely, tolerated by the polyvinyl material without causing the polyvinyl material to gel or precipitate. The gelling or precipitating of the polyvinyl material is an indication that the limit of tolerance of the boric acid has been exceeded.

It is, of course, within the scope of this invention to apply to the yarn coats cf size of various percentages other than those specifically disclosed above. It is also within the scope of the invention to apply two or more coats of these sizes to the yarn. Furthermore, a coat of a water-sensitive hydroxylated polyvinyl resinboric acid-polyethylene oxide size can be applied over a coating of another size which by itself is insuflicient for the purposes of the present invention.

As indicated above, it is desirable to provide the yarn with an anchor coat of tannic acid prior to the application of the hydroxylated polyvinyl resin-boric acid size. It should be understood that any of the various tannic acids or tannins, when used as an anchor coat in the sizing of a yarn in accordance with the present invention, lie within the scope of this invention and are considered to be included by the term tannic acid as used in the specification and claims. Good results are obtained with 0.02% to 1.5% coats of tannic acid; and particularly good results are obtained when 0.05% to 0.3% coats of tannic acid are applied to the yarn; but the anchor coat is not to be considered to be limited to these percentages. It will be apparent that numerous similar anchoring compounds may be useful as subcoats on yams to the end of more effectively binding the size composition to the yarn.

While the invention has been described with reference to the application of the water-sensitive hydroxylated polyvinyl resin-boric acidpolyethylene oxide coat from water solution, it is obvious that it can be applied from solutions containing other solvents. Similarly, it will be apparent that the anchor coat and the size coat can be applied to the yarn by other means and in other ways than those described above; namely, skein immersion treatment and continuous application by passing the yarn over a size roll dipping into the solution.

Although polyethylene oxides having molecular weights from approximately 282 to approximately 10,000 are preferred, the use of other polyethylene oxides is not to be considered as excluded from the scope of this invention.

When prepared by polymerizing ethylene oxide in the presence of small amounts of water, these polyethylene oxides have hydroxyl end groups. By polymerizing in the presence of small 5 amounts of acids, alcohols, or amides, or by re acting the ethylene oxide polymers with esterifying or etherifying agents, it is possible to prepare polyethylene oxides having end groups other than hydroxyls. For example, end groups such as CH3COO--, C2H50, CsH, Cl, CH3CONH. Low molecular weight polyethylene oxide molecules may be linked together by polyfunctional esterifying and etherifying agents such as sebacic acid, ethylene dichloride, or epichlorohydrin to increase the molecular weight.

Modifications of these types wherein the greater proportion of the molecule is made up of polyethylene oxide chains are likewise valuable for plasticizing and otherwise benefiting these sizes, and are intended to be covered by the broad term "polyethylene oxide.

Various drying oils are useful in conjunction with the size compositions of this invention. Such oils as oxidized linseed oils having iodine numbers between 90 and 105, Chinawood oil, castor oil, etc., will be found to be useful in conjunction with the sizes of this invention. Such oils may be applied as emulsions in water or in solutions in various solvents, such as ethyl alcohol, isopropyl alcohol, butyl alcohol, ethyl, methyl or butyl Cellosolve, etc. It will be apparent that the drying oil may be emulsified in the size .composition or that it may be applied to the yarn in a separate step.

An alkaline after-treatment may be applied in connection with the sizing process of this invention. The alkaline treatment tends to gel the surface of the size coat giving good running properties to the yarn. The alkaline after-treatment may be applied in numerous ways by treating the yarn with vapors or solutions of alkaline substances. By alkaline substance" is meant any substance which, when shaken with water, gives an alkaline reaction to the water.

The water-sensitive hydroxylated polyvinyl resin-boric acid-polyethylene oxide sizes of this invention may be modified with solutions or dispersions of various modifying agents for various purposes. For example, polymethacrylic acid or polymethacrylates may be used as modifying agents to improve the running qualities of these sizes. The addition of octyl alcohol also improves the running qualities. Various gums, waxes and resins, such as resorcinal formaldehyde resin, may be used as modifying agents. Fillers, such as bentonite, starches, dextrine, etc., may be used as modifying agents. Various other plasticizers, such as glycerol, the various glycols, sorbitol, glucose, diethylene glycol, triethylene glycol, ethanol formamide, glycerol glyco'llate, ethanol acetamide, tetraethylene glycol, dimethoxytetraethylene glycol, etc., may be used with these sizes. Various lubricants, such as mineral oil, olive oil, teaseed oil, other vegetable oils, sulfonated mineral oils and sulfonated vegetable oils, soaps, such as diglycol oleate, glycerol monoricinoleate, etc., may be used. These sizes may be modified also with preservatives such as orthophenyl phenol, etc. Various corrosion inhibitors, such as triethanolamine and its :fatty acid esters, diglycol oleate, morpholine, pyridine, etc., may be coated over these sizes either alone or mixed with a coning oil or finishing agent. It will be apparent that many of the materials which may be added to the sizing compositions, or applied to the sized yarn, may serve more than one purpose; for example, the same material may serve as a plasticizer and also as a lubricant, or as a plasticizer and a preservative.

Although the invention has been discussed with particular reference to multifilament yarns of synthetic linear polyamides, it will be obvious that the same compositions will be applicable as sizes to other synthetic linear polyamide structures, such as monofils, films, staple fibers, spun yarn, mixed yarn, ribbon, etc. Various structures possess to a greater or smaller extent, as the case may be, essentially the same critical sizing problems as the multifilament polyamide yarns, for the smoothness and lack of watersensitivity of the synthetic linear polyamides prevent the close adherence of the conventional sizes to the polyamide structure.

Although the sizing compositions of this invention are unique and outstanding for the sizing of synthetic linear polyamide yarns which are to be used in the knitting of sheer hosiery, they will also be useful in the sizing of other yarns and fabrics, such as cotton, silk, wool, linen, viscose rayon, cuprammonium rayon, cellulose acetate rayon, yarn prepared from synthetic linear vinyl polymers and synthetic linear ethylene polymers, etc.; for the problem of adherence of the size to the yarn is not nearly so great in the case of these other types of yarn. These sizes will be found to be particularly useful for sizing yarns which are relatively water-insensitive. It will also be obvious that these sizing compositions may be useful for sizing yarns to be used in weaving operations as well as knitting operations.

The sizes of this invention present the distinct advantage over the prior art sizes of adhering well to synthetic linear polyamide yarn while possessing other qualities desired in a size for yarn to be used in the knitting of sheer hosiery. Yams sized with the sizes of this invention and in accordance with the process of this invention knit very well, and produce sheer, full-fashioned stocking fabrics which are relatively free of snags and pulled threads. These sizes minimize edge rolling characteristics and thus assist in the more economical production of sheer, knit, full-fashioned hosiery. The sizes of this invention cause very little wear and corrosion of the needles and sinkers of the knitting machines. In knitting yarn sized in accordance with this invention, the stitch formation is very good and may be maintained uniform over long periods of time.

comparatively small amounts of these sizes are effective in protecting the multifilament polyamide yarn, 2% to 8% by weight of the size, based on the weight of the yarn, affording good protection. Since the size is easily removed from the yarn and there is not so much loss in weight of the fabric resulting from the removal of the size, polyamide yarns sized in accordance with this invention are much more desirable, for instance, in mixed fabrics with cellulose acetate rayon and other synthetic yarns than is natural silk. Natural silk has approximately 20% to 24% sericin; hence, the boil-off of natural silk results in a great loss in weight of the fabric and the removal of the sericin size is so diflicult that it not infrequently causes considerable damage to cellulose acetate rayon or other synthetic fibers present in a fabric mixed with natural silk.

Since it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited to the details described herein except as set. forth in the appended claims.

I claim:

1. A yarn sizing composition comprising a water-sensitive hydroxylated polyvinyl resin, boric acid, and polyethylene oxide.

2. A yarn sizing composition comprising an aqueous solution of a water-sensitive hydroxyl- 9.3g polyvinyl resin, boric acid, and polyethylene o e.

3. A yarn sizing composition comprising a water-sensitive hydroxylated polyvinyl resin, boric acid, and 5% to 30% (based on the weight of the polyvinyl resin) of polyethylene oxide.

4. A yarn sizing composition comprising boric acid, polyethylene oxide, and a water-sensitive hydroxylated polyvinyl resin taken from the group consisting of the partial esters of polyvinyl alcohol, the partial ethers of polyvinyl alcohol, the partial acetals of polyvinyl alcohol, and the partial ketals of polyvinyl alcohol.

5. A yarn sizing composition comprising a partially saponified polyvinyl acetate, boric acid, and polyethylene oxide.

6. A yarn sizing composition comprising a partial formal of polyvinyl alcohol, boric acid, and polyethylene oxide.

7. A yarn sizing composition comprising an aqueous solution of a partially saponified polyvinyl acetate, boric acid, and polyethylene oxide.

8. A yarn sizing composition comprising an aqueous solution of a partially saponifled polyvinyl acetate, boric acid, and polyethylene oxide, said polyvinyl acetate having a saponification number of between 40 and 220.

9. A yarn sizing composition comprising an aqueous solution of a partially saponified polyvinyl acetate, boric acid, and polyethylene oxide, said polyvinyl acetate having a viscosity of between 1.5 and 20 centipoises in a 4% water solution at 20 C.

10. The process of sizing synthetic linear polyamide yarn which comprises applying thereto a coating of tannic acid, and applying to said coated yarn a sizing composition containing a watersensitive hydroxylated polyvinyl resin, boric acid, and polyethylene oxide.

11. The process of sizing synthetic linear polyamide yarn which comprises applying thereto a 0.2% to 1.5% coating of tannic acid based on the weight of the yarn, and applying to said coated yarn a sizing composition containing a water-sensitive hydroxylated polyvinyl resin, boric acid, and polyethylene oxide.

12. A synthetic linear polyamide yarn suitable for use in the knitting of sheer, full-fashioned hosiery containing a coating of a size comprising a water-sensitive hydroxylated polyvinyl resin, boric acid, and polyethylene oxide.

13. A synthetic linear polyamide yarn suitable for use in the knitting of sheer, full-fashioned hosiery containing a coating of a size comprising a water-sensitive hydroxylated polyvinyl resin, boric acid, and 5% to 30% (based on the weight of the polyvinyl acetate) of polyethylene oxide.

14. A synthetic linear polyamide yarn suitable for use in the knitting of sheer, full-fashioned hosiery, containing a coating of a size comprising boric acid, polyethylene oxide, and a water-sensitive hydroxylated polyvinyl resin taken from the group consisting of the partial esters of polyvinyl alcohol, the partial ethers of polyvinyl alcohol, the partial acetals of polyvinyl alcohol and the partial ketals of polyvinyl alcohol.

15. A synthetic linear polyamide yarn suitable for use in the knitting of sheer, full-fashioned hosiery containing a coating of tannic acid anchoring agent, and an overcoating of a size comprising a water-sensitive hydroxylated polyvinyl resin, boric acid, and polyethylene oxide.

16. A synthetic linear polyamide yarn suitable for use in the knitting of sheer, full-fashioned hosiery containing a coating of a size comprising a partially saponified polyvinyl acetate, boric acid, and polyethylene oxide.

1'7. A synthetic linear polyamide yarn suitable for use in the knitting 'of sheer, full-fashioned hosiery containing a coating of a size comprising a partial formal of polyvinyl alcohol, boric acid, and polyethylene oxide.

DANIEL E. STRAIN. 

